#pragma ident "$Id$"

/**
 * @file SP3Header.hpp
 * Encapsulate header of SP3 file data, including I/O
 */

//============================================================================
//
//  This file is part of GPSTk, the GPS Toolkit.
//
//  The GPSTk is free software; you can redistribute it and/or modify
//  it under the terms of the GNU Lesser General Public License as published
//  by the Free Software Foundation; either version 2.1 of the License, or
//  any later version.
//
//  The GPSTk is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
//  GNU Lesser General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public
//  License along with GPSTk; if not, write to the Free Software Foundation,
//  Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA
//
//  Copyright 2004, The University of Texas at Austin
//
//============================================================================

//============================================================================
//
//This software developed by Applied Research Laboratories at the University of
//Texas at Austin, under contract to an agency or agencies within the U.S.
//Department of Defense. The U.S. Government retains all rights to use,
//duplicate, distribute, disclose, or release this software.
//
//Pursuant to DoD Directive 523024
//
// DISTRIBUTION STATEMENT A: This software has been approved for public
//                           release, distribution is unlimited.
//
//=============================================================================

#ifndef GPSTK_SP3HEADER_HPP
#define GPSTK_SP3HEADER_HPP

#include <string>
#include <map>
#include <vector>
#include "SP3Base.hpp"
#include "SP3SatID.hpp"
#include "CommonTime.hpp"
#include "TimeSystem.hpp"

namespace gpstk
{
/** @addtogroup SP3ephem */
//@{

/// This class models the header for a SP3 file.
///
/// @note A valid header MUST be read before data can be read from an SP3 file
/// because the header contains the file version or format. The version in
/// this Header is used by SP3Stream to determine the format of output SP3Data.
///
/// @sa gpstk::SP3Stream and gpstk::SP3Data for more information.
class SP3Header : public SP3Base
{
public:

    /// Supported SP3 versions (file formats) : 'a' 'b' or 'c'
    /// See the SP3 format definition documents.
    enum Version
    {
        undefined,        ///< Unknown or undefined SP3 file format
        SP3a,             ///< SP3 version a
        SP3b,             ///< SP3 version b (very similar to SP3a)
        SP3c              ///< SP3 version c (contains a/b as a subset)
    };

    /// constructor
    SP3Header() : version(undefined), numberOfEpochs(0),
        system(1, SP3SatID::systemGPS), timeSystem(TimeSystem::Any),
        basePV(0.0), baseClk(0.0)
    {}

    /// destructor
    virtual ~SP3Header() {}

    /// access the version or file format
    /// @return the current Version
    Version getVersion(void) const throw()
    {
        return version;
    }

    /// access the version or file format as a character
    /// @return a character version of the current Version
    char versionChar(void) const throw()
    {
        char ch;
        switch(version)
        {
        case SP3a:
            ch = 'a';
            break;
        case SP3b:
            ch = 'b';
            break;
        case SP3c:
            ch = 'c';
            break;
        case undefined:
        default:
            ch = 'U';
            break;
        };
        return ch;
    }

    /// access the version or file format as a string
    /// @return a string version of the current Version
    std::string versionString(void) const throw()
    {
        std::string str;
        switch(version)
        {
        case SP3a:
            str = std::string("SP3a");
            break;
        case SP3b:
            str = std::string("SP3b");
            break;
        case SP3c:
            str = std::string("SP3c");
            break;
        case undefined:
        default:
            str = std::string("Undefined");
            break;
        };
        return str;
    }

    /// set the version or file format. Note that reading an SP3 file
    /// automatically sets the version in the SP3Header object that is read.
    /// @param ver the Version to be assigned to this header
    /// @return the current Version
    Version setVersion(const Version ver) throw()
    {
        Version oldFormat = version;
        version = ver;
        return oldFormat;
    }

    /// return a string with time system name
    std::string timeSystemString() const throw()
    {
        return timeSystem.asString();
    };

    // The next four lines is our common interface
    /// SP3Header is a "header" so this function always returns true.
    virtual bool isHeader() const
    {
        return true;
    }

    /// Dump contents to an ostream
    virtual void dump(std::ostream& s=std::cout) const throw();


    ///@name data members
    //@{

    /// The SP3 version (file format) is initially undefined, but it will be
    /// assigned by reallyGetRecord() while reading, and may be reassigned
    /// by the user before writing.
    Version version;           ///< SP3 Version or file format
    bool containsVelocity;     ///< If true, file contains velocities
    CommonTime time;           ///< Time of first Epoch in file
    double epochInterval;      ///< Duration of Epoch in seconds
    int numberOfEpochs;        ///< Number of epochs in this file
    std::string dataUsed;      ///< Types of data input into the positions
    std::string coordSystem;   ///< Coordinate System of the data
    std::string orbitType;     ///< Type of Orbit Estimate
    std::string agency;        ///< Agency generating the Orbit

    // the following are specific to version 'c'
    SP3SatID system;        ///< system of satellites in file, e.g. G for GPS
    TimeSystem timeSystem;  ///< Time system used
    double basePV;          ///< Base used in Pos or Vel (mm or 10**-4mm/sec)
    double baseClk;         ///< Base used in Clk or rate (psec or 10**-4psec/sec)
    /// Map<SP3SatID,accuracy flag> (all SVs in file)
    std::map<SP3SatID, short> satList;
    /// vector of 4 comment lines
    std::vector<std::string> comments;

    //@}

    friend class SP3Data;

protected:
    /// Writes the record formatted to the FFStream \a s.
    /// @throws StringException when a StringUtils function fails
    virtual void reallyPutRecord(FFStream& s) const
    throw(std::exception, FFStreamError,
          StringUtils::StringException);

    /// This function retrieves the SP3 header from the given FFStream.
    /// If an error is encountered in the retrieval of the header, the
    /// stream is reset to its original position and its fail-bit is set.
    /// @throws StringException when a StringUtils function fails
    /// @throws FFStreamError when exceptions(failbit) is set and
    ///  a read or formatting error occurs.  This also resets the
    ///  stream to its pre-read position.
    virtual void reallyGetRecord(FFStream& s)
    throw(std::exception, FFStreamError,
          StringUtils::StringException);

}; // end class SP3Header

//@}

}  // namespace

#endif

